The large Glaucidae Nudibranch Phyllodesmium longicirrum feeding on a large leather coral on a small reef wall on an island within the Banda Sea in Indonesia.
There specialized leather coral feeder can grow up to a foot in size, and are spectacular with their numerous and lengthy 'tentacles' or cirri.
These nudibranchs are also farmers - taking the zooxanthellae from the leather corals and incorporating it into their system where they reproduce by photosynthesis.